This proposal, which is based on our previous studies of calcium phosphate chemistry and caries mechanisms, is aimed at developing agents that can more effectively prevent or reverse dental caries. 1. Two-component Fluoride Rinses. A two-component fluoride (F) rinse was developed that is significantly more effective than a sodium fluoride rinse of the same F content (250 ppm) in depositing F on enamel and root surfaces, and in plaque and saliva. This experimental rinse will be evaluated in an intraoral demineralization/remineralization model under conditions that closely mimic the clinical situation. A two-component rinse with a much lower F content, e.g., 76 ppm F, will also be evaluated in in vitro and intraoral models. The goal is to develop F rinses with greater efficacy but at lower F dosages. 2. Two-component Fluoride Dentifrices: Two-component dentifrices, that are based on the same chemistry as that for the rinses, with F contents of 1000 and 250 ppm will be evaluated in in vitro and intraoral models with the aim of developing more effective F dentifrices at lower F doses. 3. Operator-applied Fluoride Treatment Agents; Treatment with an acidic calcium phosphate and complex fluoride-containing (CPF) gel deposited significantly more loosely bound F and tooth-bound F than did the F gel currently in use clinically. In vitro and intraoral studies are proposed to evaluate the CPF gels that are designed to maximize both the loosely bound and tooth-bound F depositions for a given F dose. Studies will be conducted to develop partially dehydrated CPF gels for trayless application ot interproximal areas that are most in need of protection. 4. Thermodynamic, Kinetic, and Diffusion Considerations of Reactions in Two-component Anticaries Agents; Thermodynamic and kinetic studies are proposed to investigate reaction processes that can be utilized in two- component fluoridation or remineralization treatment processes. Diffusion studies are proposed to gain knowledge that may lead to development of sequential applications of two solutions through which the location of the mineral precipitation can also be controlled. 5. Remineralizing Chewing Gums; Chewing gums that contained calcium phosphates (selected based on their solubilities) elevated enamel supersaturation in saliva. Intraoral studies are proposed to evaluate the anticaries effect of gum formulations with different amounts and types of these additives.